The better insulated your home is, the less you spend. Having energy-efficient, renewable heat generation
in place is the first step. If your home is uninsulated, 25% of all heat lost goes through the roof..
Loft insulation is effective for at least 40 years, and it will pay for itself over and over in that time -- in an uninsulated house, most of the heat lost is through the roof.
Most houses built during and briefly after the 1920s have external walls are made of two layers with a cavity (gap) in-between them. Cavity Wall insulation fills that gap, keeping the warmth in for longer. It can also reduce condensation inside the house, if this is a typical issue.
If your walls are solid, then insulation will reduce your energy bills drastically, as these let through twice as much heat as cavity walls do. Solid walls, can be insulated from the inside, outside or both.
Insulation under the floorboards on your ground floor will save you around 60 GBP per year, and you can seal the gaps between floors and skirting boards to reduce draughts too.
Often overlooked and one of the cheapest, most efficient methods save energy in any type of building.